Due to the expanding, worldwide use of personal computing devices, telecommunications devices and the Internet, the global economy is currently undergoing an information revolution that is expected to be as significant as the industrial revolution of the nineteenth century. A significantly large population of people, however, are generally underserved and dissatisfied with their telecommunications options and are therefore presently limited in their ability to participate in this information revolution. This population of people is primarily located in Africa, Central America, South America and Asia, where communication services have, to date, been characterized by the poor sound quality of short-wave radio broadcasts, or the coverage limitations of amplitude modulation (AM) band and frequency modulation (FM) band terrestrial radio broadcast systems.
A satellite-based direct radio broadcast system to transmit audio and data signals, including images, to low-cost consumer receivers in essentially any part of the world has been proposed. The satellite-based direct radio broadcast system provides a number of advantages over existing satellite systems, such as the ability to provide portable services. Many existing satellite systems fail to provide portable services because they require large satellite antennas to access such systems.
Low earth orbit (LEO) satellite systems are currently used to serve mobile and portable users. In addition, a number of geostationary satellite systems can provide portable or mobile communication services. However, existing LEO and geostationary satellite systems do not provide adequate channel capacity to provide the high outbound data rates required for transmission of information from the Internet and the World Wide Web (WWW) to many different users.
Systems have been proposed to use satellites to provide worldwide Internet/WWW access capability to fixed-site users. For example, systems which use geostationary satellites and multiple spot beams (e.g., Hughes Spaceway and Loral Cyberstar) have been proposed, as well as systems comprising hundreds of satellites in a geodesic dome-like arrangement around Earth or in multiple orbits (e.g., Teledesic). These systems, however, fail to provide global, portable Internet/WWW access capability.
A satellite-based direct radio broadcast system, however, is limited in that the receivers are one-way and do not permit a user to transmit voice or other information. Users of these receivers, therefore, cannot communicate bi-directionally via the satellite-based direct radio broadcast system and, accordingly, do not have access to the Internet. Thus, a need exists for a low-cost user terminal which provides users with the advantages of a satellite-based direct radio broadcast system (e.g., large geographic coverage, good sound quality, high outbound data rates and low cost), as well as bi-directional communication for global, portable Internet/WWW access capability.